.columns {
    width: 500px;
    padding: 5px;
    border: 1px solid green;
    margin: 20px auto; 
    columns:140px 3;/*列宽 列数*/
    column-gap:2px;/*列间距*/
    column-rule-width:2px;
    column-rule-color:blueviolet;
    column-rule-style:inset;/* 和border-style属性值一样，默认none,包括hidden,dotted,
    dashed,solid,double,groove,ridge,inset,outset*/
column-span:all;/*none|all*/
}
h2{
    background: green;
    padding: 10px;
    color: #fff;
  }
h2,
p:nth-child(2n){
  -webkit-column-span:all;
  -moz-column-span:all;
  -o-column-span:all;
  -ms-column-span:all;
  column-span:all;
}